pub fn odd_fibnacci_sum(threshold: u32) -> u32 {
    if threshold <= 1 {
        return 0;
    }
    let (mut a, mut b) = (0, 1);
    let mut res = 1;
    loop {
        (a, b) = (b, a + b);
        if b < threshold {
            if b & 1 == 1 {
                res += b;
            }
        } else {
            break res;
        }
    }
}
